Automatic elevation recovery system for cannons

ABSTRACT

In a cannon system, a change in the elevation angle of the cannon tube is converted to angular displacement of the yoke trunnions of the forward tripod support of the cannon tube. This angular displacement is sensed by a fluidic sensor which transmits a corresponding signal to a fluidic amplifier whereby the signal is amplified and transmitted to a cylinder for actuation of a piston therein responsive to the signal. The cylinder, piston and a piston rod form one leg of the tripod and the linear displacement of the piston acts to change the elevation of the tube to where it returns to the pre-selected angle of elevation as sensed by the sensor.

United States Patent n91 LaSpisa et al.

1 Sept. 25, 1973 AUTOMATIC ELEVATION RECOVERY SYSTEM FOR CANNONSInventors: Ronald J. LaSpisa, North Tonawanda; Gary W. Woods,Rensselaer, both of NY.

The United States of America as represented by the Secretary of theArmy, Washington, DC.

Filed: Apr. 7, 1972 Appl. No.: 242,004

Assignee:

89/37 L, 40 E, 41 H, 41 CE References Cited UNITED STATES PATENTSLeathers et al. 89/41 H Primary Examiner-Stephen C. BentleyAttorney-Harry M. Saragovitz et al.

[57] ABSTRACT In a cannon system, a change in the elevation angle of thecannon tube is converted to angular displacement of the yoke trunnionsof the forward tripod support of the cannon tube. This angulardisplacement is sensed by a fluidic sensor which transmits acorresponding signal to a fluidic amplifier whereby the signal isamplified and transmitted to a cylinder for actuation of a pistontherein responsive to the signal. The cylinder, piston and a piston rodform one leg of the tripod and the linear displacement of the pistonacts to change the elevation of the tube to where it returns to thepre-selected angle of elevation as sensed by the sensor.

8 Claims, 7 Drawing Figures AUTOMATIC ELEVATION RECOVERY SYSTEM FORCANNONS The invention described herein may be manufactured, used andlicensed by or for the Government without the payment to us of anyroyalty thereon.

BACKGROUND OF THE INVENTION This invention relates to cannons andpertains more particularly to a control device for automaticallyrecovering the adjusted elevation of a cannon when displaced therefrom.

Oftentimes cannons, because of the exigencies of war, have to be mountedon unstable terrain which permits the cannon to be displacedsufficiently responsive to recoil forces to move the cannon off target.This is particularly true of infantry mortars which are packed to areas,often of rough terrain, and then quickly set up, sighted on the targetand fired. In such instances, a number of projectiles have to be tiredbefore the mortar base plate is sufficiently entrenched to withstandfurther recoil forces without appreciable displacement. Consequently,mortars have to be resighted after firing each of the initial roundsand, as the only hitherto known practical means of resighting a mortaris by manual means, the resighting takes considerable critical time tothereby reduce the firepower of the mortar. Means have been attemptedherebefore to automatically realign mortars with a target but they havebeen placed on the base plate which is subjected to flying debris duringfire and even of being buried where the supporting terrain is sandy.Thus, the automatic mechanisms become fouled and consequentlyinoperable.

SUMMARY OF THE INVENTION It is one object of this invention to providefor cannons a control system which automatically reestablishes theelevation thereof whenever displaced during fire from an adjustedsetting.

It is a further object of this invention to provide such a system whichis fluid actuated.

It is a still further object of this invention to provide such anautomatic control system which is simple in design, compact in size,rugged in construction and reliable in operation.

These .objects are achieved by adapting for cannon use the inventionwhich is disclosed in our copending patent application for "FluidActuated Control System," US. Pat. Ser. No. 242005; Filed: Apr. 7, 1972.In this adaptation a change in the elevational angle of the cannon isconverted to angular displacement of the sleeve trunnions which are partof the tripod support of the front end of the cannon tube. This angulardisplace ment is sensed by a fluidic sensor which transmits a signalresponsive to the angular displacement to a fluidic amplifier wherebyfluid of unbalanced pressure is transmitted to opposite ends of acylinder for linear actuation of a piston therein. The cylinder, pistonand connecting piston rod form one leg of the tripod and the lineardisplacement of the piston serves to change the elevation of the cannontube until it returns to the adjusted elevation as sensed by the sensor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of amortar system shown sighted on a target and with the cylinder of theautomatic recovery system partially broken away to show the piston andconnected piston rod therein;

FIG. 2 is a view similar to FIG. 1 but shows the base plate drivenrearwardly, thereby misaligning the tube axis relative to the sight lineof elevation;

FIG. 3 is a view similar to FIGS. I and 2 but shows the elevation of thecannon tube recovered by the recovery system;

FIG. 4 is an enlarged fragmentary view of the mounting yoke of thetripod and the sleeve pivotally, mounted thereto, with the yoke shownpartially in cross-section to disclose the sensing device therein;

FIG. 5 is a section taken-along line 55 of FIG. 4;

FIG. 6 is a schematic view of the fluidic amplifier; and

FIG. 7 is an isometric, exploded view of the sensing device exclusive ofthe yoke arm in which it is mounted and with the sleeve frag'mentized toshow the interior structure of the device.

DESCRIPTION OF A PREFERRED EMBODIMENT Shown in the drawings is a mortarsystem 12 comprising a firing tube 114, a base plate 16 pivotallymounted to the rear end thereof and a tripod 18 which slidingly supportsthe front end of the tube. Base plate 16 is provided with a plurality ofspikes 20 which project downwardly from the under side thereof so as tobe entrenched into the supporting terrain responsive to the recoilforces produced in tube 14 when a projectile is fired therefrom.

Tripod 18, as shown in FIGS. 1-3, comprises a cylinder 22 whichslidingly accommodates a piston 24 with a piston rod 26 attachedthereto. Cylinder 22, with piston 24 and piston rod 26, form the leg oftripod 18 which is coincident with a vertical plane defined by thelongitudinal axis of tube 14. The other two legs 28 of tripod 18 areattached to the upper end of cylinder 22 so as to spread oppositely andoutwardly therefrom. A spiked plate 30 extends from the bottom end ofcylinder 22 and similar spiked plates extend from the bottom ends oflegs 28 to secure tripod 18 against displacement when the spikes aredriven into the supporting terrain.

The outer end of piston rod 26 is terminated by a yoke 32 having a pairof spaced arms 34 which receive therebetween a sleeve 36 having a bore37 that slidingly receives tube 14, allowing both linear and angulardisplacement relative thereto. Sleeve 36 is mounted to arms 34 forpivotal rotation about a diametrical axis by means of a pair oftrunnions which include an axle 38 threaded into the outer circumferenceof the sleeve and a shaft 40 threaded thereinto in diametrical alignmentwith the axle. Shaft 40 includes a bearing portion 42 and a rotorportion 44 which extends outwardly therefrom and which is part of asensing device 45 to be described hereinafter. Rotor 44 is connected tobearing portion 42 by means of a screw 46 having a head 48 of largerdiameter. Screw 46 is received by a hole 50 which is axially boredthrough rotor 44 and counterbored at 52 to a shoulder 54 and which isthreadingly engaged with a threaded bore 56 in bearing portion 42. Thus,when screw 46 is loosened, rotor 44 is free to be rotated thereaboutsrelative to hearing portion 42 and, when the screw is tightened, therotor is frictionally secured to the bearing portion against angulardisplacement. Manual rotation of rotor 44 is facilitated by a I knurledgripping portion 55.

Axle 38 is received by a bushing 58 in one arm 34, as shown in FIG. 4.Shaft 40 extends through astepped hole 59 in the opposite one of thearms 34 which is counterbored at 60 from the outside thereof to ashoulder 62. A sleeve 63 of sensing device 45, having a bore 61, isinstalled in counterbore 60 by press fit and a bushing 64 is installedin the smaller diameter portion of hole 59 for bearing contact withbearing portion 42.

A pair of segmental slots 65 are symmetrically formed in sleeve 63 fromthe outside circumference thereof, as shown in FIG. 5. Slots 65 areclosed by the circumferential surface of counterbore 60 to define aright chamber 66 and a left chamber 67. A bottomed hole 68 extendsradially inwardly from the circumference of sleeve 63 equidistant fromthe bottom ends of right chamber 66 and left chamber 67 and such holehas registry with a passage 69 in the respective one of the arms 34.Such passage 69 has communication with a source of low pressure fluidflow, (not shown) at approximately -7 psi, by means of a conduit 70.Fluid communication between hole 68 and chambers 66 and 67 is providedby restrictive orifices 72 and 74, respectively, which are disposed 180apart in sleeve 63 and which have their axes normal to and intersectingwith the axis of such hole.

Provided in rotor 44 where encircled by sleeve 63 is a pair of similarsegmental channels 76 which are oppositely disposed and which areangularly related to each other with bottom edges 78 thereofdiametrically spaced. The upper ends of channels 76 are interrupted by asegmental cut 80 which extends along rotor 44 to the free end thereof,as shown in FIGS. 5 and 7. Channels 76 are partially closed by thecircumferential surface of bore 61 to define a right passage 82 and aleft passage 84. Both passages 82 and 84 have fluid communication withan opening 86 which is defined by segmental cut 80 and thecircumferential surface of bore 61. Fluid communication between rightpassage 82 and right chamber 66 is provided by an aperture 88 and asimilar aperture 90 provides communication between left passage 84 andleft chamber 67. Apertures 88 and 90 are disposed 180 apart and in axialalignment so that both may be simultaneously bisected by the respectiveone of the edges 78 when rotor 44 is disposed at a pre-selected angularposition, as shown in FIG. 5, and wherein an index line 91 on grippingportion 55 is in alignment with a calibration 93 on outer face 95 ofsleeve 63.

Thus, when the low pressure fluid flow from conduit 70 is permitted topass into hole 68 it passes therefrom equally through right orifice 72into right chamber 66 and through left orifice 74 into left chamber 67.From chambers 66 and 67 the low pressure fluid passes as two signalflows through an outlet 92, leading from right chamber 66, and anotheroutlet 94, leading from left chamber 67, and also through the respectiveapertures 88 and 90, as controlled by the angular position of rotor 44,to passages 82 and 84 and therefrom to the ambient atmosphere.Consequently, the pressure and volume of the signal flows passingthrough outlets '92 and 94 are controlled by the amount of the fluidflow vented through apertures 88 and 90 from chambers 66 and 67,respectively, to thereby generate and transmit to outlets 92 and 94fluidic signals relative to the angular position of rotor 44. When rotor44 is rotated to where edges 78 divide apertures 88 and 90 equally, asshown in FIG. 5, the pressure and volume of the signal flows passingthrough outlets 92 and 94 are the same. When rotor 44 is rotated to anangular position whereby the opening between left aperture and leftpassage 84 is decreased, and the opening between right aperture 88 andright passage 82 is increased, the amount of the signal flow passingthrough outlet 94 is proportionally greater than that passing throughoutlet 92 and thereby produces a signal, transmitted through suchoutlet, which indicates the angular position of the rotor respective tothe pre-selected angular position. The degree of angular displacement ofrotor 44 which will produce a proportional signal is determined by thesize of apertures 88 and 90, Le, the greater the size of theseapertures, as measured on or along the circumference of bore 61, thegreater is the angular displacement of the rotor which will produce aproportional signal. When, through greater angular displacement of rotor44, one of the apertures 88 and 90 is closed and the other is fully opena maximum differential signal is produced and transmitted from sensingdevice 45 by means of the fluid pressure which passes through outlets 92and 94.

Outlets 92 and 94 connect, respectively, with input ducts 96 and 98 of afluidic amplifier 100 which is of conventional type and is fullyexplained in the inventors hereinbefore referenced copendingapplication. Input ducts 96 and 98 communicate at a 180 angle withajunction 102 to which a high pressure fluid flow at approximately 30psi is conducted by conduit 104 from a source (not shown). Two branches,including a left passage 105 and a right passage 106, extend fromjunction 102 in a Y" configuration so that the high pressure fluid flowmay be directed into either passage with no loss in momentum.Proportional deviation of the high pressure fluid flow at junction 102into passages 105 and 106 is controlled by the signal flows conducted tothe junction by means of input ducts 96 and 98.

As shown in FIG. 1, piston 24 is of double acting type and cylinder 22is closed at one end and a seal is made at the opposite end where pistonrod 26 extends therefrom. Right passage 106' is connected by conduit 107to the top end of cylinder 22 and left passage 105 is connected byconduit 108 to the bottom end of the cylinder so that piston 24 isdisplaceable therein according to the amplified signal transmitted bythe controlled fluid flow to the cylinder.

OPERATION When mortar system 12 is set up on a supporting terrain, asshown in FIG. 1, with the longitudinal axis of cylinder 22 beingsubstantially coincident with the vertical plane defined by bore axis xxof tube 14, the tube is sighted on the target by sighting means (notshown) so that axis xx is coincident with the adjusted angle ofelevation y-y. With tube 14 sighted on the target, screw 46 is loosenedand rotor 44 is turned through gripping portion 55 until index line 91is aligned, with calibration 93 Thus, sensing device 45 is in balancewith rotor 44 and disposed at the preselected angular position. Screw46is then tightened so that rotor 44 is angularly displaceable togetherwith sleeve 36.

When a projectile is fired from tube 14, the recoil force is transmittedto base plate 16 and, if the terrain is not fully stable and spikes 20are not driven thereinto to fix the base plate to the terrain, the baseplate is driven rearwardly and downwardly, as shown in FIG. 2. Becauseof this displacement of base plate 16, axis x-1 the rotor isconsequently displaced angularly therewith,

as explained hereinbefore, whereby responsive signals are transmitted tofluidic amplifier MN). The signals received by fluidic amplifier 1100are amplified and directed to opposite sides of piston 24 proportionalto the difference between the two signal flows transmitted to thefluidic amplifier. Consequently, piston rod 26 with sleeve 36 areactuated upwardly, and forwardly along tube lid, to return bore axis x-xback to the adjusted angle of elevation y-y. When angular displacementof rotor 44 by rotation of sleeve 36 reaches the preselected angularposition the adjusted angle of elevation y-y of tube M is recovered andmortar system H is back on target as to elevation. if the displacementof base plate 16 rotates rotor 44 to where the angular displacementthereof is beyond the limits wherein the sig nals from sensing deviceare proportional, a maximum differential signal is produced until therotor is returned within the limits wherein the proportional signals areeffected, thereby expediting the return of mortar system 1 2 intoalignment with the target.

We wish it to be understood that we do not desire to be limited to theexact details of the construction shown and described for obviousmodifications will occur to a person skilled in the art.

We claim:

ii. A cannon system comprising a projectile discharging tube disposedfor angular displacement to an adjusted angle of elevation for sightingat a target, fluid actuated means for automatically recovering theadjusted angle of elevation of said tube responsive to displacementtherefrom, said fluid actuated means including a sensing deviceresponsive to angular displacement of said tube from the adjusted angleof elevation and means for generating a low pressure fluid signalaccording to the angular displacement, a fluidic amplifier foramplifying the low pressure signal to a fluid flow of greater pressure,and means responsive to the amplified fluid flow for returning said tubeto the adjusted angle of elevation.

2. The invention as defined in claim 1 and including means forsupporting the rear end of said tube, and means for supporting the frontend of said tube, and wherein said means responsive to the amplifiedfluid flow comprises means for displacing one of said supporting meansresponsive to displacement of said tube from the adjusted angle ofelevation for recovery thereto.

3. The invention as defined in claim 2 wherein said means for supportingthe front end of said tube comprises a tripod including three spacedlegs, and said means responsive to the amplified signal comprises acylinder with a cooperating piston and a piston rod, and wherein saidcylinder, piston and piston rod form one leg of said tripod.

d. The invention as defined in claim 3 wherein said 7 means responsiveto the amplified signal comprises a yoke mounted to said piston rod, anda sleeve pivotally mounted to said yoke, said sleeve having a boreadapted to slidingly receive said tube for angular and longitudinaldisplacement relative thereto.

5. The invention as defined in claim 4 wherein said yoke includes a pairof spaced arms, said sleeve includes a pair of trunnions for pivotallymounting said sleeve to said arms, and wherein one of said trunnionsincludes at least one element of said sensing device.

6. The invention as defined in claim 5 wherein said one element of saidsensing device includes a rotor, and wherein said sensing device alsocomprises a sleeve mounted in one of said arms for receiving said rotor,and said rotor and said sleeve include cooperating means for sensing theangular displacement of said sleeve from a selected angular position andgenerating a t'luidic signal reflecting the degree of the angulardisplacement.

7. The invention as defined in claim 6 and including means foradjustably mounting said rotor for angular displacement relative to saidsleeve to thereby adjust the selected angular position of said rotor 50as to coincide with the adjusted angle of elevation of said tube.

8. The invention as defined in claim 7 and including means indicatingcoincidence of the'sel'ected angular position of said rotor and theadjusted angle of elevation of said tube.

1. A cannon system comprising a projectile discharging tube disposed forangular displacement to an adjusted angle of elevation for sighting at atarget, fluid actuated means for automatically recovering the adjustedangle of elevation of said tube responsive to displacement therefrom,said fluid actuated means including a sensing device responsive toangular displacement of said tube from the adjusted angle of elevationand means for generating a low pressure fluid signal according to theangular displacement, a fluidic amplifier for amplifying the lowpressure signal to a fluid flow of greater pressure, and meansresponsive to the amplified fluid flow for returning said tube to theadjusted angle of elevation.
 2. The invention as defined in claim 1 andincluding means for supporting the rear end of said tube, and means forsupporting the front end of said tube, and wherein said means responsiveto the amplified fluid flow comprises means for displacing one of saidsupporting means responsive to displacement of said tube from theadjusted angle of elevation for recovery thereto.
 3. The invention asdefined in claim 2 wherein said means for supporting the front end ofsaid tube comprises a tripod including three spaced legs, and said meansresponsive to the amplified signal comprises a cylinder with acooperating piston and a piston rod, and wherein said cylinder, pistonand piston rod form one leg of said tripod.
 4. The invention as definedin claim 3 wherein said means responsive to the amplified signalcomprises a yoke mounted to said piston rod, and a sleeve pivotallymounted to said yoke, said sleeve having a bore adapted to slidinglyreceive said tube for angular and longitudinal displacement relativethereto.
 5. The invention as defined in claim 4 wherein said yokeincludes a pair of spaced arms, said sleeve includes a pair of trunnionsfor pivotally mounting said sleeve to said arms, and wherein one of saidtrunnions includes at least one element of said sensing device.
 6. Theinvention as defined in claim 5 wherein said one element of said sensingdevice includes a rotor, and wherein said sensing device also comprisesa sleeve mounted in one of said arms for receiving said rotor, and saidrotor and said sleeve include cooperating means for sensing the angulardisplacement of said sleeve from a selected angular position andgenerating a fluidic signal reflecting the degree of the angulardisplacement.
 7. The invention as defined in claim 6 and including meansfor adjustably mounting said rotor for angular displacement relative tosaid sleeve to thereby adjust the selected angular position of saidrotor 50 as to coincide with the adjusted angle of elevation of saidtube.
 8. The invention as defined in claim 7 and including meansindicating coincidence of the selected angular position of said rotorand the adjusted angle of elevation of said tube.